Hessonite?

[Jksonner1]

Or Spessarite??? It's neghbor Emerald too. Any input? I think this is a beautiful stone. Root beer colored. WIll make a ring out of it for myself. The flashed out pieces to the right left are the same thing only two smaller oval cuts.

 

[Lee Little]

It would take test to be sure but I would guess Spessartite rather than Hessanite in that color. Best regards, Lee

 

[Richard M.]

I don't think I agree with Lee on this one. That hue is classic for hessonite aka "cinnamon stone." There's a simple observation that could provide a clue to ID. If you have a 10-power loupe inspect the stone for what are known as Scotch whisky or treacle inclusions -- a wispy, wavy internal appearance that some say resembles heat waves inside the stone. Not all hessonites have them but they're pretty typical.

An RI test should be conclusive. Spessartite tests at or above the limit and yields a much more brilliant stone. Hessonite tests lower, around 1.734-1.759 and isn't especially brilliant.

Richard M. (Rick Martin)

 

[movie zombie]

i'm with Rick on this one: hess and spess colors do overlap but this one looks "classic" hess to my eye.....

btw, i love the cut! its quite the stone! congrats and please post when its been set. not all hess is created equal and i think you've got a nice one.

 

[Jksonner1]

Thanks all for the great input. I will take a closer look with a loop. I have had them weighed for carats as well when I picked most of them up. I forget how many carats though. Looking for a scale locally today. Thinking about one of those Gem-n-Eye testers too. Any input on those. I feel I will be a hobbiest at least in this as long as my job continues to have me traveling to gem rich countries.

 

[Richard M.]

The Gem-n-Eye is just an offshoot of the reflectivity meter. Its software has been jiggered to give readings digitally like a regular critical angle refractometer but that's the only similarity. Reflectivity meters are notorious for their inaccurate readings because they depend on the quality of a stone's polish. A bad polish or a slightly dirty stone give incorrect results. I have no experience with that specific machine but I own two reflectivity meters and have found them virtually useless. Mine need to be recalibrated after nearly every reading.

One more thing: garnets are among the most difficult gems to accurately identify and classify. Even a refractometer won't always help because several species and mixtures are over its limit for readings. A spectroscope is the "weapon of choice" for garnets.

Richard M. (Rick Martin)

 

[Jksonner1]

Good to know. Thank you good Sir.

 

[Jksonner1]

A GG told me it tested as Sapphire after running it through a refractometer.

 

[Lee Little]

Synthetic or Be treated perhaps?

 

[LD]

A GG told me it tested as Sapphire after running it through a refractometer.

My guess is that his refractometer either needs calibrating or he doesn't know how to read it correctly. If it didn't test as garnet then you may be looking at a synthetic.

However, I would guess not as it looks like a classic Hessonite.

 

[Lee Little]

I would hope that a GG would know how to use a refractometer and would have one that is accurate but the title does not guarantee anything. Best regards, Lee

 

[innerkitten]

Wow it does look like rootbeer. I don't know which it is but it's pretty.

 

[innerkitten]

How does a refractometer work and what does it look like?

 

[LD]

There are different types and this is a basic one. Mine looks like a souped up version of this but has a built in light source.

You open it up and put a refractive oil onto the little glass window you can see in the middle. Put the gem on it and close the lid very gently. You then shine a light down through the back of it and look into the viewing window. You should then see a green line and light/shade on what looks like a measuring tape that indicates the RI.

It sounds easy but it can take some time to do it properly.

 

[innerkitten]

Pretty cool. Thanks for that!

 

[chrono]

I'm very surprised at the result because that isn't a typical sapphire look. If so, I would suspect it to be synthetic at best.

 

[davi_el_mejor]

Hessonite RI 1.734-1.759

Sapphire RI 1.762 - 1.778

Almandine Garnet RI 1.77 - 1.82

So close in RI that someone not taking the time or having quality equipment could misjudge.


Regardless it's a pleasing color and good size

 

[innerkitten]

So it looks more like a hessonite but could be a sapphire. Sapphires do come in every color so I don't see why not. Of course then you have to determine if it's natural or synthetic.

 

[Lee Little]

Even though the basic number is similar, with a refractometer it should be a very easy call because they all have a polarizing lens thus a Garnet will have only one reading even with the polarizer while Sapphire will certainly differ. Unless a GG is really rusty, he will catch this elementary difference. Best regards, Lee